Flash units for still cameras are usually mounted on the camera and are oriented so that flash illumination extends substantially parallel to the axis of the optical path of the camera lens. This results in substantially direct, sometimes intense, illumination of the subject or scene being photographed. This illumination is frequently disadvantageous because round, curved or irregularly shaped surfaces, such as those of a human face appear, unnaturally flat. In addition, direct lighting creates photographs having shadows on, or alongside, the subject or on nearby walls. When taking color photographs of a subject's face while using direct illumination, the subject's eyes frequently appear red instead of having their natural color.
To minimize the problems associated with direct illumination, it has become the practice to orient flash reflectors so that at least a component of the flash illumination does not parallel the optical axis of the camera lens bounces off an adjacent surface such as a ceiling. This provides indirect, more diffused illumination of the scene or subject being photographed.
The patent literature includes a number of patents directed to such a procedure: specifically, U.S. Pat. Nos. 4,122,333; 4,233,648; 3,869,604, and 4,512,644. The patent literature also includes U.S. Pat. Nos. 4,122,333; 3,869,604 and 4,233,648 which disclose the concept of having a pivotal bounce flash member. While these bounce flash illuminators are pivotally mounted, there is no provision with these illuminators for selecting the bounce angle automatically. U.S. Pat. No. 4,512,644 discloses a flash device having a servo controlled illuminating angle, however, the illuminating angle is determined according to the focal length of the camera lens and the servo controller is switched off when the flash illuminator is operated in a bounce flash mode.
In view of the aforementioned considerations there is a need for an approach for automatically selecting the angle at which a flash unit, or other illuminating device, directs its illumination toward the ceiling of a room when practicing bounce illumination of a subject or scene.